Regulator for diving

ABSTRACT

A regulator for diving includes a pressure regulating means. The pressure regulating means includes a multiple thread screw  87  operatively thread-engaged with a slider  84  which, in turn, is pressed a pressure regulating coil spring  81  so that this coil spring  81  is adjusted from the maximum compressed condition to the minimum compressed condition as the multiple thread screw  87  is fully turned.

TECHNICAL FIELD

The present invention relates to a regulator for diving and more particularly to such a regulator suitable to be used as a regulator usually referred to as a second stage.

BACKGROUND ART

A regulator for diving is well known, which comprises a basic structure adapted to be kept in air-tight condition so long as a diver is using it, a built-in pressure-controllable air supply mechanism provided in the basic structure, a mouthpiece connected to the basic structure and a check valve mounted on the basic structure so as to be switched between its opened and closed positions. An example of the air supply mechanism comprises a pressure control knob, a screw member adapted to be rotated as the knob is rotated and a slider in thread-engagement with the screw member. The slider moves forward or backward with respect to an axial direction of the screw member as the latter is rotated. This slider is pressed against a coil spring biasing the check valve in an axial direction of this coil spring so that the coil spring may be compressed or relaxed as the slider moves forward or backward. In this manner, a pressure of the air supplied from the air supply mechanism to the diver can be regulated.

With such a regulator of prior art, the air pressure can be regulated by rotating the knob since the knob can be rotated by a plurality of turns. However, such regulator of well known art makes it difficult, depending on the diver, to identify a level at which the air pressure is set by his or her own regulator. Furthermore, if the knob must be rotated by a plurality of turns in order to obtain a desired pressure level, operation of air pressure regulation is troublesome for the diver.

It is an object of the present invention to improve a regulator for diving so that somewhat troublesome knob manipulation required by the conventional regulator can be alleviated and a desired pressure level can be quickly set.

DISCLOSURE OF THE INVENTION

According to the present invention, there is provided a regulator for diving comprising a basic structure adapted to be kept in substantially air-tight installed so long as a diver is actually using it, a pressure-controllable air supply mechanism installed in the basic structure, a mouthpiece connected to the basic structure and a check valve attached to the basic structure so as to be operated between opened and closed positions.

The air supply mechanism further comprises a tubular housing connected to an air supply source lying outside the basic structure and a tubular joint member adapted to be joined to the housing within the basic structure in an axial direction of the housing and extending outwardly beyond the basic structure. There are provided in the axial direction of the housing, inside the housing and joint member, a pressure reducing valve member acting upon the air flowing from the supply source into the housing, a coil spring having one end acting upon a rear side of the valve member and a pressure regulating means acting upon the other end of the coil spring opposed to the one end so as to compress or relax the coil spring, and a pressure regulating means comprises a screw member extending in the axial direction of the housing and mounted on the joint member so as to be rotatable around the axis, the screw member having an inner end extending into the housing and an outer end extending outwardly from the housing, the inner end being formed with multiple threads, a slider mounted within the joint member in a manner that the slider can move slidingly in the axial direction of the housing but can not rotate around the axis and is operatively thread-engaged with the multiple thread screw. An inner end of the slider contacts with the opposite end of the coil spring and outside the basic structure is formed a knob adapted to rotate the screw member on the outer end of the screw member.

The present invention includes several preferred embodiments as follows:

The multiple thread screw is of a type having 2-4 threads and a lead of this multiple thread screw is formed so that approximately a single turn of the screw member may cause the slider to depress the coil spring from a maximum compressed condition to a minimum compressed condition.

The knob is provided with a ratchet mechanism adapted to control a rotational angle of the knob.

The ratchet mechanism comprises a concave-convex shaped member interposed between a region of the basic structure opposing to the knob and the knob and a spring means adapted to be selectively engaged with or disengaged from the concave-convex shaped member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the regulator according to the invention;

FIG. 2 is an exploded perspective view of the regulator;

FIG. 3 is a sectional view taken along a line III—III in FIG. 1;

FIG. 4 is a sectional view taken along a line IV—IV in FIG. 1;

FIG. 5 is a view similar to FIG. 4 showing the regulator during air supplying;

FIG. 6 is a perspective view of the lever;

FIG. 7 is a partially cutaway side view showing the housing;

FIG. 8 is a view similar to FIG. 7 showing the housing with the lever mounted thereon;

FIG. 9 is a sectional view taken along a line IX—IX in FIG. 8; and

FIG. 10 is an exploded perspective view showing fragmentarily the basic structure of the regulator.

PREFERRED EMBODIMENTS OF THE INVENTION

Details of a regulator for diving according to the present invention will be more fully understood from the description given hereunder in reference to the accompanying drawings.

A regulator 1 shown in FIG. 1 by a perspective view is connected via a first stage (not shown) to a low pressure hose 2 extending from an air reservoir carried on a diver's back when the regulator 1 is used. The regulator 1 basically comprises a basic structure 3 and a mouthpiece 4 made of elastically flexible plastics. The basic structure 3 comprises a main body 5 made of rigid plastics, a flexible diaphragm cover 6 lying on the front side of the main body 5, first and second rigid retaining members 7, 8 for the cover 6, and an exhaust duct 9 lying on the rear side of the main body 5 extending right- and leftward as viewed in FIG. 1. An end of the low pressure hose 2 connected to the main body 5 is covered with a sleeve 11 on its left side as viewed in FIG. 1 and a pressure control knob 12 is positioned on its right side as viewed in FIG. 1.

FIG. 2 is an exploded perspective view showing fragmentarily the regulator 1. When the first retaining member 7 fixed by screw to the front side of the main body 5 may be unscrewed from the main body 5, the second retaining member 8 and the diaphragm cover 6 together with the first retaining member 7 are disengaged from the main body 5. Inside the main body 5 are provided a diaphragm 10 and a tubular housing 13 containing therein a pressure control mechanism and on its rear side with a check valve 14 made of flexible elastic plastics (See FIG. 4 also). The diaphragm 10 made of a material usually used for this purpose is pressed air-tightly against a seal surface 16 formed on the periphery of the inner surface of the main body 5 by the first retaining member 7 screwed on the main body 5. The housing 13 is transversely extending through the main body 5 in such a manner as air-tightness is maintained between the housing 13 and the main body 5. A lever 17 extends from the housing 13 toward the diaphragm 10 and an extension 22 extends from a deflector 21 toward the mouthpiece 4.

FIG. 3 is a sectional view taken along a line III—III in FIG. 1. On the peripheral wall 23 of the tubular housing 13 are provided with a first air outlet port 24 and a second air outlet port 26 (See FIG. 7 also). A tubular portion 27 of the deflector 21 is positioned slightly apart outwardly from the peripheral wall 23 forming a space 28 between these peripheral wall 23 and tubular portion 27. In the tubular portion 27 is provided with an air inlet 29 in substantially the same alignment with the first air outlet port 24. The extension 22 has its proximal end 22A at the edge of the air inlet port 29 and extends outwardly in a radial direction of the housing 13. A distal end 22B of the extension 22 extending from its proximal end 22A lies in the vicinity of a joint section 31 of the basic structure 3. The mouthpiece 4 is secured around the joint section 31 by a band 4A.

The lever 17 extending from the housing 13 has its distal end 17A positioned adjacent to the inner surface of the diaphragm 10 or pressed against the diaphragm 10 with a reinforcing plate 33 therebetween. In the vicinity of the outer surface of the diaphragm 10, there is a projection 34 extending from the inner surface of the diaphragm cover 6.

The check valve 14 lying on the rear side of the main body 5 is disc-shaped and mounted on the main body 5 by fitting a projection 36 formed in the central port of the check valve 14 into a through-hole 37 of the basic structure 3. The duct 9 lies behind the check valve 14.

When a diver tries to inhale the air with the mouthpiece 4 held in his or her mouth, an air pressure inside the basic structure 3 lying on the right side of the diaphragm as viewed in FIG. 3 is reduced and the diaphragm 10 is moved to a direction indicated by an arrow A pushing the lever 17. The lever 17 pushed in this manner functions to open an air inlet valve (air supply valve) 72 (See FIG. 4) and the air flows from the low pressure hose 2 into the housing 13. A portion of the air flowing into the housing 13 flows out through the first outlet port 24 lying in front of the air supply valve 7 as viewed in the air flowing path in the housing 13, then flows through the air inlet port 29 to a direction indicated by an arrow B and its flow is obstructed by the extension 22 of the deflector 21 as it flows from below as viewed in FIG. 3. In consequence, this partial amount of the air flows to the mouthpiece 4 through a path indicated by an arrow C with its velocity reduced. Another portion of the air flowing into the housing 13 flows out through the second outlet port 24 of the housing 13 and, after obstructed by the inner surface of the tubular portion 27 of the deflector 21, flows in directions indicated by arrows D₁, and D₂ at a reduced velocity in the space 28, then flows out through the inlet port 29 obstructed by the extension 22 and then finally flows to the mouthpiece 4. When a diver exhaled the air toward the basic structure 3, the diaphragm 10 and the lever 17 return to the respective positions as shown in FIG. 3 and simultaneously the air supply valve 72 in the housing 13 is closed to stop further air supply. The air exhaled opens the check valve 14 as indicated by imaginary lines and is exhausted via the duct 9. The extension 22 and the tubular portion 27 of the deflector 21 are spaced outwardly in a radial direction from the first outlet port 24 and the second outlet port 26, i.e., lie immediately above these outlet ports 24, 26, respectively, so as to cover them. The extension 22 covers the inlet port 29 also from immediately above.

FIG. 4 is a sectional view taken along a line IV—IV in FIG. 1. The housing 13 housed in the main body 5 extends outwardly through a first through-hole 41 of the main body 5 opening on the left side as viewed in FIG. 4 and a nut 43 is screwed on this extension 42. The low pressure hose 2 is secured around a distal end of this extension 42 by a nut 44. As seen on the right side of FIG. 4, a tubular joint member 47 extending outwardly through a second through-hole 46 of the main body 5 is screwed on the right end of the housing 13. A flange 48 formed on the-right end of the joint member 47 is pressed against the main body 5 on its right side with an annular spacer 49 therebetween. On the opposite side, the nut 43 screwed on the extension 42 of the housing 13 is pressed against the main body 5 from its outside and the left. In this manner, the housing 13 is fixed to the main body 5.

The tubular portion 27 of the deflector 21 fit around the housing 13 in this manner has its longitudinally opposite ends 27A, 27B kept in close contact with the outer surface of the housing 13 and its intermediate portion 27C spaced from a diameter-reduced portion 13A of the housing 13 with the space 28 between the intermediate portion 27C and the outer surface of the housing 13. In this diameter-reduced portion 13A, the first and second outlet ports 24, 26 are formed allowing fluid flow between inner side the housing 13 and the space 28. The inlet port 29 of the deflector 21 lies above the first outlet port 24 as viewed in FIG. 4. The second outlet port 26 is so formed to have an opening area equal to or larger than that of the first outlet port 24 (See FIG. 7). The position of the extension 22 of the deflector 21 is offset from a center line CL bisecting a width of the joint section 31 of the basic structure 3 toward the right side as viewed in FIG. 4 and the extension 22 is pressed against an inner peripheral wall 31A of the joint section 31 from inside. The housing 13 is provided with an O-ring 51 placed against the end 27B of the deflector 21 from the right side to prevent the deflector 21 from moving rightward as viewed in FIG. 4.

As will be seen on the left side of FIG. 4, an air guide tube 62 is screwed around the periphery of the inner wall of the housing 13. This air guide tube 62 has a front end 63 offset toward the middle region of the main body 5 so as to form an orifice and a rear end 66 offset toward the outer end region of the main body 5 keeping in close contact with the inner surface of the housing 13 with an O-ring 64 therebetween. The front end 63 of the tube 62 is provided on its front face with a fluorine-treated seal surface 63A and on its outer surface with a thread 63B by which the front end 63 is secured to the inner surface of the housing 13. A rear end 66 of the tube 62 is formed on its inner surface with a screw thread 67. The air supply valve 72 for pressure reduction made of silicone rubber attached to a rear end 73 of a cylindrical stem member 71 is pressed against the seal surface 63A of the tube 62 from the right side as viewed in FIG. 4.

The stem member 71 has, in addition to the valve 72 and the rear end 73, an intermediate portion 74 extending on the right side of the rear end 73 and a front end 76-extending on the right side of the intermediate portion 74 so that the stem member 71 may have its outer diameter gradually reduced from the rear end 73 toward the front end 76. The rear end 73 is formed with a recess 77 adapted to receive an inner end 17B (See FIG. 6) of the lever 17. A guide member 78 is mounted around the intermediate portion 74 in such a manner as the guide member 78 can not rotate in a circumferential direction of this intermediate portion 74.

The guide member 78 is in contact with the inner surface of the housing 13 in such a manner as the guide member 78 can slide in the circumferential direction as well as in the axial direction of the housing 13. The front end 76 of the stem member 71 extends from the front end 79 of the guide member 78 (See FIG. 9).

A rear end 82 of a coil spring 81 is pressed against the front end 79 of the guide member 78. A front end 83 of the coil spring 81 is pressed against a rear end 86 of a slider 84 housed in the joint member 47.

The slider 84 is fit in an axial bore 48A of the joint member 47 in such a manner as the slider 84 can move in the axial direction but can not move in the circumferential direction of the joint member 47. In the axial bore 48A, there is provided a pressure control screw member 85 which can not move in the axial direction but move in the circumferential direction of the member 47 and the slider 84 is securely screwed around a multiple thread screw 87 formed on the rear end of the pressure control screw member 85.

The pressure control screw member 85 is protected by a nut 88 screwed into the front end 47A of the joint member 47 against falling off from the joint member 47. The knob 12 is mounted on a front end 87A of the screw member 85 by means of a set screw 91 so as to lie on the exterior of the main body 5. The set screw 91 has its threaded shank 91A screwed into the front end 87A of the screw member 85. A circular leaf spring 92 is interposed between the flange 48 of the joint member 47 and the knob 12. The leaf spring 92 is fixed to the inner surface 12A of the knob 12 and adapted to rotate together with the knob 12 (See FIG. 10).

Though not explained in details, an appropriate O-ring is interposed between each pair of mutually contacting members in order to keep the interior of the basic structure 3 in a substantially air-tight condition.

With the regulator 1 constructed as has been described above, the valve 72 is biased by the coil spring 81 to be pressed against the seal surface 63A of the tube 62 and thereby to prevent the air from flowing from the low pressure hose 2 into the housing 13. Inhalation of the air retained in the basic structure 3 by a diver deforms the diaphragm 10 which resultantly moves the lever 17 so that the inner end (proximal edge) 17B of the lever 17 may shift the stem member 71 rightward as viewed in FIG. 4 against the spring 81. Thereby the valve 72 is separated from the seal surface 63A allowing the air to flow from the low pressure hose 2 into the housing 13.

FIG. 5 is a view similar to FIG. 4, showing a state in which the valve 72 is opened allowing the air to flow from the low pressure hose 2 into the housing 13. As shown, the diaphragm 10 is deformed to push the outer end (distal edge) 17A of the lever 17 and the resultant movement of the lever 17 makes the valve 72 to be drawn away from the seal surface 63A. A gap 60 is formed between the valve 72 and the seal surface 63A and the air flows through the gap 60 into the housing 13.

Referring to FIGS. 4 and 5, a force exerted on the seal surface 63A by the valve 72 is controlled by varying a degree of compression of the spring 81 by rotating the knob 12. More specifically, this operation of adjustment is carried out as follows. First, the multiple thread screw 87 is rotated by rotating the knob 12 so that the slider 84 may linearly slide left- or rightward as viewed in FIGS. 4 and 5 to compress further or depress the spring 81. More strongly the spring 81 is compressed, more forcibly the spring 81 causes the guide member 78 to press the valve 72 against the seal surface 63A. To separate the valve 72 in such a state from the seal surface 63A, a force sufficiently strong to overcome the compressive force must be exerted upon the lever 17. The slider 84 slides rightward as viewed in FIGS. 4 and 5 until the flange 86A formed on its front end comes in contact with the end surface 85A of the screw member 85 and slides leftward as viewed in FIGS. 4 and 5 until the flange 86A comes in contact with a shoulder 47B of the joint member 47. A lead of the multiple thread screw 87 is preferably set so that the slider 84 slides over a full stroke defined between the end surface 85A and the shoulder 47B as the knob 12 makes a full rotation. With this, the diver can easily understand an approximate level at which the air pressure is adjusted on the basis of an angular position of the knob 12.

The air introduced into the housing 13 flows in such directions as indicated by arrows B, C, D₁, D₂ in FIG. 3 to the diver's mouth. In the course of the air flow toward the diver's mouth, the air flow is obstructed by the deflector 21 whereupon the air has its flow velocity decreased and its flow width spread, facilitating the diver to inhale the air. Such pattern of air flow is also effective in avoiding a phenomenon of free flow of the air often occurring inside the basic structure 3 accompanied by the air flow from the housing 13, thereby preventing a degree of vacuum in the basic structure 3 from rising to an unacceptably high level. To make such effect more reliable, it is preferable to make an opening area of the second outlet port 26 of the housing 13 larger than that of the first outlet port 24. Such arrangement of the deflector 21 as laterally offset from the middle of the mouthpiece advantageously eliminates such apprehension as the supplied air might stimulate the diver's mouth from the front and, in addition, the deflector 21 might obstruct the diver's exhaling. The deflector 21 is directly mounted on the housing 13 so as to cover the first and second outlet ports 24, 26 from immediately above. Such arrangement effectively reduces the velocity of air flow.

As the tube 62 has its seal surface 63A treated with Teflon, the valve 72 can smoothly leave this seal surface 63A and it is reliably avoided that the valve 72 might be substantially fixed in close contact with the seal surface 63A and could not be easily separated from the seal surface 63A even after the regulator 1 has not been used for a long period of time. The tube 62 is formed on the inner surface of its rear end 66 with the thread 67. For maintenance and/or checking of the regulator 1, the tube 62 may be unscrewed from the housing 13 and then an appropriate bolt may be engaged with the thread 67 of the tube 62 to pull the bolt together with the tube 62 out from the rear end (the left side as viewed in FIGS. 4 and 5). In this way, the tube 62 can be quickly withdrawn from the housing 13 without any anxiety that the tube 62 might be damaged during this operation. Alternatively, the thread 67 may be previously configured so that the threaded shank 91A of the set screw 91 can be utilized as the bolt to eliminate the demand for the separately prepared bolt used for maintenance and/or check of the regulator 1.

FIG. 6 is a perspective view of the lever 17, FIG. 7 is an exploded side view showing the housing 13 as the region in which the lever 17 is mounted on the housing 13 has been cutaway, FIG. 8 is an exploded side view showing the housing 13 with the lever 17 mounted thereon as partially cutaway and FIG. 9 is a sectional view taken along a line IX—IX in FIG. 8. It should be understood that the housing 13 shown in FIGS. 7, 8 and 9 has the sleeve 62 and the stem member 71 (indicated by imaginary lines) mounted thereon but the other members such as the deflector 21 dismantled therefrom. Referring to these figures, the lever 17 is a metallic member having a substantially rectangular frame-like structure comprising the outer end 17A placed against the diaphragm 12, the inner end 17B partially received in the housing 13 and a pair of lateral sides 17C extending in parallel to each other between the outer and inner ends 17A, 17B. The inner end 17B is oriented perpendicular to an axis of the housing 13 extending horizontally as viewed in FIG. 7 and has a front surface 20A and a rear surface 20B. The inner end 17B presents a rectangular shape which is relatively long in vertical direction (See FIG. 8).

Now a procedure for mounting the lever 17 on the housing 13 will be described. The housing 13 is formed on its peripheral surface with a first cutout 101 diametrically extending in vertical direction as viewed in FIG. 7 and diametrically extending across the housing 13 as viewed in FIG. 9 and a second cutout 102 extending leftward (as viewed in FIG. 7) from the lower end of the first cutout 101 in the axial direction of the housing 13. The left end of the second cutout 102 defines a vertical end surface 103. The rear end 73 (See FIG. 4) of the stem member 71 has already been inserted into the housing 13 from the right side (See FIG. 4) as indicated by imaginary lines and the recess 77 of the rear end 73 lies at substantially the same vertical position as the first cutout 101. The housing 13 is inserted into the frame structure forming the lever 17, then the inner end 17B is inserted into the first cutout 101 in a direction indicated by an arrow P and the stem member 71 is received in the recess 77. Thereafter the inner end 17B is moved together with the stem member 71 leftward as shown in FIGS. 8 and 9 until the rear surface 20B of the inner end 17B is pressed against the end surface 103 of the second cutout 102 and the recess 77 of the stem member 71 has its wall surface 73A pressed against the front surface 20A of the inner end 17B. Then the deflector 21 is mounted on the housing 13 in a direction indicated by an arrow Q in FIG. 7. With the lever 17 mounted on the housing 13 in this manner, the wall surface 73A of the stem member 71 is pressed against the front surface 20A of the inner end 17B and the rear surface 20B of the inner end 17B is pressed against the end surface 103 of the housing 13 under the biasing force of the spring 81. In this manner, the lever 17 is held in its state as shown in FIG. 4. The inner end 17B of the lever 17 tilts (See FIG. 5) from its substantially vertical position as the lever 17 is pushed by the diaphragm 10 as seen in FIG. 5. As a result, the stem member 71 is moved forward (rightward as viewed in FIG. 8) against the force of the spring 81 to generate the gap 60. The stem member 71 restores its state shown in FIG. 5 as the diaphragm 10 restores its initial position.

According to the present invention, as the lever 17 in a form of a frame-like structure as shown in FIG. 6 is not easily deformed and its shape is stabilized, its handling is very easy. It is also possible to divide the inner end 17B of the lever 17 along a center line P—P and to dimension the lateral sides 17C to be relatively short as is the case with some of the conventional regulators. Obviously, such configuration has a problem that the respective lateral sides 17C can independently move, the lever is likely to be deformed. However, the housing 13 according to the present invention can overcome this problem. Specifically, the lever 17 can be easily mounted on the housing 13 merely by inserting the inner end 17B of the lever 17 into the first and second cutouts 101, 102 of the housing 13 no matter form of configuration how the lever 17 may take. It is not required for a diver to deform the lever 17 in order to mount the lever 17 on the housing 13 and therefore even a deformable lever as has often been used in a regulator of prior art can effectively function in the regulator according to the present invention.

FIG. 10 is an exploded perspective view fragmentarily showing the joint member 47 and the knob 12. On the surface of flange 48 of the joint member 47 facing the knob 12, a plurality of grooves 106 extending in a radial direction of the flange 48 are formed and arranged at regular intervals in a circumferential direction. On the inner surface 12A of the knob 12 are provided with a plurality of projections 12B and a circular or horseshoe-shaped leaf spring 92 is attached to the inner surface 12A by inserting bent portions 92A of the leaf spring 92 into a gap defined between each pair of the adjacent projections 12B. On the inner surface 12A are additionally provided with projections 12C adapted to support the leaf spring 92 with an appropriate flexibility. The leaf spring 92 is provided with a projection 92B which is convex toward the flange 48. The front end 87A of the screw member 85 is inserted into a through-hole 12D of the knob 12 to make the leaf spring 92 attached to the knob 12 contact with the flange 48 and the set screw 91 is screwed into the front end 87A of the screw member 85 from outside of the knob 12. The joint member 47 inclusive of the flange 48 is fixed to the main body 5 and the screw member 85 integrated with the knob 12 rotates relatively to the joint member 47. When the knob 12 is rotated, the projection 92B of the leaf spring 92 is alternately engaged and disengaged with the grooves 106, providing the knob 12 a ratchet function.

The deflector 21 of the regulator 1 according to the present invention is mounted on the outer side of the housing 13 so as to cover the first and second outlet ports 24, 26 for air supply from immediately above. So far as such feature is concerned, the present invention can be implemented with the housing 13 having only the first outlet port 24 or only the second outlet port 26, i.e., without any restriction on the number of the air inlet ports. For the housing 13 having only the second outlet port 26, it is also possible to use the deflector 21 comprising the tubular portion 27 only without the extension 22.

The regulator according to the present invention is primarily characterized in that the coil spring acting upon the pressure reducing valve can be adjusted from the maximum compressed condition to the minimum compressed condition by a full rotation of the pressure regulating knob. In other words, the diver can easily identify the regulated pressure level on the basis of the angular position of the knob. The ratchet mechanism combined with the knob assists the diver to identify the regulated pressure level. 

What is claimed is:
 1. A regulator for diving comprising a basic structure adapted to be kept in substantially air-tight condition so long as a diver is actually using said regulator, a pressure-controllable air supply mechanism installed in said basic structure, a mouthpiece connected to said basic structure and a check valve attached to said basic structure so as to be operated between opened and closed positions, said regulator further comprising: said air supply mechanism comprising a tubular housing connected to an air supply source lying outside said basic structure, the tubular housing defining an axis, and a tubular joint member adapted to be joined to said tubular housing within said basic structure and along said axis and extending outwardly beyond said basic structure wherein there are provided inside said housing and joint member, a pressure reducing valve member acting upon the air flowing from said supply source into said housing, a coil spring having one end acting upon a surface of said valve member and a pressure regulating means acting upon another end of said coil spring opposed to said one end so as to compress or relax said coil spring; wherein said pressure regulating means further comprises comprising a screw member mounted on said joint member so as to be rotatable around said axis, said screw member having an inner end extending into said housing and an outer end extending outwardly from said housing, said inner end being formed with multiple threads, a slider mounted within said joint member in a manner that said slider can move slidingly along said axis said housing but not rotatably around said axis, said slider operatively thread-engaged with said multiple threads of said screw member wherein an inner end of said slider contacts with said another end of said coil spring; and wherein a knob is located outside said basic structure and is adapted to rotate said screw member on an outer end of said screw member, said knob being provided with a ratchet mechanism adapted to control rotation of said knob.
 2. The regulator according to claim 1, wherein said multiple thread screw is threaded a lead of said multiple thread screw is formed so that approximately a single turn of said screw member may cause said slider to depress said coil spring from a maximum compressed condition to a minimum compressed condition.
 3. The regulator according to claim 1, wherein said ratchet mechanism comprises a concave-convex shaped member interposed between a portion of said basic structure opposing to said knob and said knob and a spring means adapted to be selectively engaged with or disengaged from said concave-convex shaped member. 